Known chargers of this type generally receive their reserve of fibers pneumatically, by manual charging or from a charging bin. The reserve rests on a receptacle apron, is seized by a spiked apron, is detached therefrom by the doffer and falls in the adjustable discharge hopper with an oscillating wall. Delivery cylinders then move this supply onto the feed apron feeding the carding machine.
At present, the control of all these members is effected in the following way: a photoelectric cell controls the level of fibers in the reserve and, as soon as a predetermined height of fibers is achieved, the cell is occluded, giving a stop signal to the fan feeding the clumps of fibers. When the level of the fibers in the receptacle falls below the level of the cell, such that the cell is again triggered, the fan bringing the fibers is restarted. The thickness of the fiber mat which the spiked apron conveys toward the hopper is controlled by another cell placed adjacent said spiked apron.
The charging of the spiked apron is effected according to the same principle as that of the receptacle, which is to say the thickness of the fiber mat is controlled by the cell which is occluded when said thickness is too great, which sends a stop signal to the charger and, when the thickness of the mat is returned to normal, the cell is triggered and controls a return to operation of the charger.
A third cell is disposed at the entrance to the hopper and is adapted to control the stopping or starting of the charger, according to the same principle as that described above, as a function of the height of the material located in the hopper.
The different control points of the charger control it totally or not at all, which is to say stopping it or starting it, which has several drawbacks for the charger of a carding machine.
Thus, the adjustment of the thickness of the layer of material which the charger must deliver to the carding machine is difficult to regulate, such that the carding machine is fed in an irregular manner and the resulting product is also irregular, of doubtful quality, which gives rise to large variations in the specific weight of the mass of fibers.
Moreover, the conveyance of the material toward the carding machine is necessarily discontinuous because the operation of the charger is discontinuous and subject to numerous stops and starts which gives rise to the same drawbacks described above, namely, an irregular product and poor quality resulting in large variations of the specific weight of the mass of fibers.
Finally, the different constituent devices such as the receptacle apron, the spiked apron, the delivery cylinders and the movable regulator are controlled by a constant speed motor, such that there is a lack of flexibility, which also contributes to the irregularity of feed of the carding machine.